The authorities of the American city of Philadelphia have issued a curfew to stop new demonstrations and riots.
The city has been troubled for several days since an African-American man was shot by police.
The man had a knife and was said to be in a bad state at the time of the incident.
No one is allowed on the street from 9 p.m. to 6 a.m.
The measure already appears to be successful on Wednesday evening (local time).
A protest should have taken place earlier in the evening, but it was called off when only a dozen people showed up.
However, four people were arrested for not adhering to the curfew.
On Monday and Tuesday evening, major protests took place that ended in riots, accompanied by vandalism and looting.
172 people have been arrested in total and 53 police officers have been injured.
The protests began Monday hours after images surfaced online of the death of 27-year-old black American Walter Wallace.
He was holding a knife and ignoring police orders to drop it.
As Wallace got closer to two officers, fourteen shots were fired at him by the pair.
According to Wallace's family, they called the police because the man might be in psychosis.
Demonstrators and police clash again after black man's death in Philadelphia
Protesters see Wallace's death as an example of excessive police brutality
According to protesters, Wallace's death is the latest example of excessive police brutality against black Americans.
The Philadelphia rallies follow a wave of protests since George Floyd's death in May.
He died after a cop pushed his knee against his neck for nearly nine minutes.